Liquid control system



Aug.. l, 1944- w. McK. MARTIN LIQUID CONTROL SYSTEM Filed Dec. 15 1941 ATTOENEYS l Patented ug. 1.,A 1944 LIQUID CONTROL SYSTEM William McK. Martin, Maywooll1l., assignor to American Can Company, New York, N. Y., a corporation of New Jersey Application December 13, 1941, Serial No. 422,918

4 Claims.

The present invention relates to an apparatus for conveying through pipe lines liquids that have -a tendency to foam when agitated in the presence of air and has particular reference to maintaining the pipe lines free of entrained air and foam.

In handling certain kinds of liquid products, homogenized milk for example, it has been found that excessive foaming sometimes takes place due -to entrainment of air as the liquid ows from one place to another. In dairies, homogenized milk is usually passed through a, cooler and pumped through supply lines to a suitable storage tank from which it is drawn as required for lling into containers.

The coolers usually receive the milk in batches at more or less irregular periods of time. The pump must be operated for peak load of the cooler and in order to insure against inadequate pump capacity it is necessary that the pump-operate at a speed which will give a pump flow slightly in excess of the normal cooler flow. As a result there are times when the pump com- `pletely drains the cooler and thereby draws air into the supply lines. This air becomes entrained in the milk and it has been found that it is this entrained air that forms the foam in the lines and causes considerable diillculty.

The instant invention contemplates overcoming this difficulty by providing devices for regulating the level of the milk entering the supply line from the cooler by recirculating the milk when this cooler level approaches the low danger level. 'I'his is done automatically by passing the'milk through a by-pass supply line to keep the milk in the line in motion without lowering its surface level, thus preventing aeration of the milk in the line.

An object-therefore is the provision of devices 'for preventing aeration of liquid pumped through a supply line wherein a float valve and a continuously operating pump drawing liquid from a source of supply through a pipe line by-passes the liquid through a return pipe line when the liquid at the source falls to a predetermined low level so that this low level will not be lowered further thereby preventing the entrance of air into the line at the liquid source.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawing, discloses a preferred vembodiment'. thereof.

Referring to the drawing: v

Figure 1 is a schematic view illustrating an ap- (Cl. 10S-41) paratus embodying the instant invention, with paits broken away and parts shown in section;

Fig. 2 is an enlarged sectional view through a 5 portion of a float tank having a iloat valve used in the apparatus.

As a preferred embodiment of the invention the drawing illustrates a pipe line for conveying homogenized milk from a cooling device Il to a storage reservoir I2 from which it may be used as required for filling into containers. In this apparatus, milk introduced at various timesy into the cooling device flows down over corrugated surfaces Il through which a suitable cooling medium is circulated. The cooled milk runs off the bottom of the cooling surface structure and is caught in a. drip trough I5 located therebeneath.

The bottom of the drip trough I5 is connected by a horizontal supply line I5 to a larger diameter feed pipe I'I. One end of the feed pipe Il is connected to a rotary pump I8 which is continuously operated in any suitable manner. The discharge side of the pump is connected by a vertical discharge supply pipe 2| which merges into a horizontal supply pipe 22 connected to a side of the storage reservoir I2 near the top thereof. A pipe 23 which is a continuation of the pipe 22 is disposed inside the reservoir and leads to a place of discharge for the milk near the bottom of the reservoir.A These pipes 2l, 22, 23 are of the same diameter as the main supply pipe I6.

35 Hence milk from the cooler drip trough I5 flows through the main supply pipe I6 into the feed pipe Il and is forced by the pump I8 up through the pipes 2|, 22, 23 into the storage reservoir I2 for use as hereinbefore explained.

4o Provision is made for stopping this ow of milk when the milk in the drip trough I5 reaches a predetermined low level. For this purpose the feed pipe I1 at its end opposite the pump I8 is connected into a side of a float tank 26, the feed 45-pipe being connected to the tank near its bottom. The opposite side of the float tank, near its bottom, is formed with a pipe opening 2l which is normally closed by a hinged valve 2B. The valve 28 is attached to an actuating rod 29 carrying a ball float 3| which rides on the surface of the milk in the oat tank. The float tank at its pipe opening 21 is connected by a vertical by-pass pipe 3l and a continuing horizontal by-pass pipe 35, to the vertical discharge pipe 2|, as shown in the drawing. These by pass pipes are of the same diameter as the supply pipe I6 and the discharge pipes 2|, 22, 23.

With this construction of apparatus, milk from the cooler drip trough II tllls the iioat tank 20 to the same level as the milk in the trough. With the milk in the trough at high level the ball iloat 3| in the iioat tank keeps the valve 2l closed. Although the by-pass pipes 2l, 3B are filled with milk at al1 times, the closed valve 28 prevents its circulation through the pipes. Hence normally, the pump Il only forces the milk from the drip trough up through the supply pipes 2| 22, 2l into the storage tank.

However, as the milk level in the drip trough Il recedes. the milk level in the float tank 26 also recedes and this permits the ball float to i'all and thus open the valve 28. When this valye is open. the milk in the by-passl pipes 3l, Il flows down into the oat tank while the pump continues operating. This opens the by-pass system and as the pump continues to operate it draws the milk from the iloat tank instead of the drip trough and f orces it up the discharge pipe 2|, where it flows through the path vof least resistance, which path is through the by-pass pipes.

Hence the milk continues circulating through the iioat tank 26, pump I8, discharge pipe 2|, and by-pass pipes 3l, 35 without drawing any of the milk from the main supply line I8. .In this manner the low level of the milk in the cooler drip trough l! is maintained at a level above the outlet of the trough, i. e., the entrance to the main supply line, and hence air is prevented from entering the line and is prevented from becoming entrained in the milk. It is this action that prevents foam from being formed and from being drawn down into the pipe lines.

When the level oi' the milk in the cooler drip trough Il again is raised by the addition of more milk `to the cooler, this milk raises the level of the milk in the float tank28. lRaising of the milk level in the tank liftsthe ball oat 3| and this closes the valve 28. Closing of the valve stops the circulation of the milk through the by-pass pipes ll, 35 and thus the milk forced through the discharge pipe 2| from the main supply line I5, ilows over into the storage reservoir I2.

Thus the cutting-in and the cutting-out of the by-pass feature of the apparatus is eieoted automatically as the pump continues to operate and r hence the maintaining of the low milk level in the cooler drip trough I5 is eiiected without any attention from the operator. f

It is thought that the invention and manyof its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacriilcing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

l. In a pipe line system for conveying a liquid from one place to another, the combination of a drawn, a pump connecting with said trough outlet for removing liquid from said trough at a rate of ilow in excess of that of the liquid entering the trough, a storage tank located above said trough and connected with said pump for receiving the aas-aces liquid from said pump and from said trough, and means for by-passing the liquid between said tank and said pump and for returning it to the pump when the liquid in said trough reaches a predetermined low level whereby said pump is operated continuously without further reducing the said predetermined low level in said trough.

2. In a pipe line system for conveying milk or the like liquid from one place to another, the combination of a trough having an outlet from which the milk is drawn, a main supply pipe line connecting with said trough outlet, a continuously operating pump connecting with said main pipe line, a discharge pipe line connecting with said pump, a storage tank located above said pump for receiving milk from the pump by way oi' said discharge pipe line, a by-poss line 'connecting with said discharge pipe line and with said main pipe line, and a valve in said by-pass line adapted to open when the liquid in the trough falls below a predetermined level, thereby setting up a temporary circulation of the milk by the pump through the by-pass means as long as the milk in the trough remains below said level to prevent further lowering of liquid in the trough and to prevent air from entering the pipe lines and becoming entrained in the milk.

3. In a pipe line system for conveying milk from one place to another, the combination of a trough having an outlet from which milk is drawn, a main supply pipe line connecting with said trough outlet, a continuously operating pump connecting with said main pipe line, a discharge pipe line connecting with said pump, a

storage tank located above said pump for receiving milk therefrom by way oi' said discharge pipe line, a float tank also connecting with said pump, a by-pass pipe line connecting with said discharge pipe line and with an inlet opening in said float tank, and a float actuated valve in said iloat tank and normally closing oil' the inlet opening in the iloat tank, said float tank being in communication with said main pipe line and maintaining milk irom said trough at a level of the milk in the trough, said iloat actuated valve operating to open the inlet into the iloat tank when the milk in the trough falls to a predetermined low level to permit 0f the circulation of the milk in the iloat tank through the by-pass pipe line while holding the milk in the trough against receding below its low level to maintain the outlet of the trough covered with milk so that air will be prevented from entering the pipe lines and from becoming entrained in the milk.

4. In a pipe line system for conveying milk or other liquid, the combination of a trough receivtrough having an outlet from which the liquid is ing a substantially continuous ilow of milk and having an'outlet from which the milk is with` drawn, a supply pipe line connecting with said outlet, a pump connecting into said pipe line and adapted to transfer the milk from the trough through said line to a point above said trough, a by-pass leading from the discharge side of said pump to said trough, a valve normally closingsaid by-pass and adapted to open when the liquid in said trough falls below a predetermined level, thereby to permit recirculation of milk through said by-pass as long as the milk in said trough remains below said predetermined level.

WIILIAM MCK. 

